Electrosurgical forceps

ABSTRACT

An electrosurgical forceps includes first and second shaft members and first and second jaw members extending distally from the respective first and second shaft members. A pivot couples the first and second shaft members with one another such that the first and second shaft members are movable relative to one another between a spaced-apart position and an approximated position to move the first and second jaw members relative to one another between an open position and a closed position. The jaw members are configured to facilitate tissue treatment, tissue division, and blunt tissue dissection.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/158,930, filed Oct. 12, 2018, the entire contents of which are herebyincorporated by reference.

BACKGROUND

The present disclosure relates to electrosurgical instruments and, moreparticularly, to an electrosurgical forceps that facilitates tissuetreatment, tissue division, and blunt tissue dissection.

A surgical forceps is a plier-like instrument which relies on mechanicalaction between its jaws to grasp tissue. Electrosurgical forceps utilizeboth mechanical clamping action and electrical energy to treat tissue,e.g., coagulate, cauterize, and/or seal tissue.

Typically, once tissue is treated, the surgeon has to accurately severthe treated tissue. Accordingly, many electrosurgical forceps have beendesigned which incorporate a knife configured to effectively dividetissue after treating tissue. Of course, the knife may also be utilizedto divided tissue without or prior to tissue treatment.

Electrosurgical forceps are also often utilized for blunt tissuedissection such as, for example, in order to provide access tounderlying tissue(s) to be treated and/or divided.

A design challenge is thus presented with respect to the design of anelectrosurgical forceps and, more specifically, with respect to strikinga balance between the benefits that certain features may provide tofacilitate some aspects (tissue treatment, tissue division, and/or blunttissue dissection, for example), versus the challenges that suchfeatures may provide to other aspects (tissue treatment, tissuedivision, and/or blunt tissue dissection, for example).

SUMMARY

As used herein, the term “distal” refers to the portion that is beingdescribed which is further from a surgeon, while the term “proximal”refers to the portion that is being described which is closer to asurgeon. Further, to the extent consistent, any of the aspects describedherein may be used in conjunction with any or all of the other aspectsdescribed herein.

An electrosurgical forceps provided in accordance with aspects of thepresent disclosure includes first and second shaft members and first andsecond jaw members extending distally from the respective first andsecond shaft members. Each of the first and second jaw members includesa distal tip portion defined as an area within a concave side of acurved distal perimeter of the distal tip portion. A pivot couples thefirst and second shaft members with one another such that the first andsecond shaft members are movable relative to one another between aspaced-apart position and an approximated position to move the first andsecond jaw members relative to one another between an open position anda closed position. A ratio of a width of the distal tip portion of eachof the first and second jaw members to a length of the distal tipportion of each of the first and second jaw members is in a range offrom about 1.45 to about 1.70.

In an aspect of the present disclosure, the ratio is in a range of fromabout 1.50 to about 1.65; in another aspect, the ratio is in a range offrom about 1.55 to about 1.60; in still another aspect, the ratio isabout 1.57.

In an aspect of the present disclosure, the distal tip portion of eachof the first and second jaw members defines a half-ellipse, and thecurved distal perimeter defines a half-circumference of thehalf-ellipse.

In another aspect of the present disclosure, the width is a minordiameter of the half-ellipse and/or the length is a major radius of thehalf-ellipse.

In yet another aspect of the present disclosure, each of the first andsecond jaw members is curved along a portion of a length thereof.

In still another aspect of the present disclosure, a lockboxconfiguration surrounds the pivot.

Another electrosurgical forceps provided in accordance with aspects ofthe present disclosure includes first and second shaft members and firstand second jaw members extending distally from the respective first andsecond shaft members. Each of the first and second jaw members includesa distal tip portion defined as an area within a concave side of acurved distal perimeter of the distal tip portion. A pivot couples thefirst and second shaft members with one another such that the first andsecond shaft members are movable relative to one another between aspaced-apart position and an approximated position to move the first andsecond jaw members relative to one another between an open position anda closed position. A ratio of a height defined between theoutwardly-facing sides of the first and second jaw members at the distaltip portions thereof in the closed position to a length of the distaltip portion of each of the first and second jaw members is in a range offrom about 2.25 to about 2.55.

In an aspect of the present disclosure, the ratio is in a range of fromabout 2.30 to about 2.50; in another aspect, the ratio is in a range offrom about 2.35 to about 2.45; in still another aspect, the ratio isabout 2.40.

In another aspect of the present disclosure, the distal tip portion ofeach of the first and second jaw members defines a half-ellipse, thecurved distal perimeter defines a half-circumference of thehalf-ellipse, and the length is a radius of the half-ellipse.

In yet another aspect of the present disclosure, the height is measuredat a diameter of the half-ellipse of the distal tip portion of each ofthe first and second jaw members.

In still another aspect of the present disclosure, each of the first andsecond jaw members is curved along a portion of a length thereof.

In still yet another aspect of the present disclosure, in the closedposition, the distal tip portions of the first and second jaw membersdefine a gap distance therebetween of equal to or less than about 0.025inches.

Still another electrosurgical forceps provided in accordance withaspects of the present disclosure includes first and second shaftmembers and first and second jaw members extending distally from therespective first and second shaft members. Each of the first and secondjaw members defines a longitudinal axis and a curved distal sectioncurving off of the longitudinal axis. The curved distal section of eachof the first and second jaw members defines a length and includes adistal tip portion defined as an area within a concave side of a curveddistal perimeter of the distal tip portion. A pivot couples the firstand second shaft members with one another such that the first and secondshaft members are movable relative to one another between a spaced-apartposition and an approximated position to move the first and second jawmembers relative to one another between an open position and a closedposition. A ratio of the length of the curved distal section of each ofthe first and second jaw members to a distance the distal tip portion ofeach of the first and second jaw members is displaced from therespective longitudinal axis of that jaw member is in a range of fromabout 2.40 to about 2.80.

In an aspect of the present disclosure, the ratio is in a range of fromabout 2.50 to about 2.70; in another aspect, the ratio is in a range offrom about 2.55 to about 2.65; in still another aspect, the ratio isabout 2.60.

In another aspect of the present disclosure, the distal tip portion ofeach of the first and second jaw members defines a half-ellipse, thecurved distal perimeter of each of the first and second jaw membersdefines a half-circumference of the half-ellipse, and the length and thedistance are measured to a point where a symmetrically bisecting radiusof the half-ellipse meets the curved distal perimeter.

In still another aspect of the present disclosure, each of the first andsecond jaw members further includes a straight proximal section centeredon the longitudinal axis thereof, the curved distal section extendingfrom the straight proximal section. In aspects, the straight proximalsection defines a length of up to about 0.125 inches.

In yet another aspect, the curved distal section of each of the firstand second jaw members defines an angle of curvature of about 15 degreesto about 25 degrees; in aspects, about 17 degrees to about 23 degrees;and, in other aspects, about 19 degrees to about 21 degrees.

Another electrosurgical forceps provided in accordance with the presentdisclosure includes first and second shaft members and first and secondjaw members extending distally from the respective first and secondshaft members. Each of the first and second jaw members defines alongitudinal axis and a curved distal section curving off of thelongitudinal axis. The curved distal section of each of the first andsecond jaw members defines a width at the proximal end thereof. Thecurved distal section of each of the first and second jaw membersincludes a distal tip portion defined as an area within a concave sideof a curved distal perimeter of the distal tip portion. The distal tipportion of each of the first and second jaw members defines a diametertransversely thereacross. A pivot couples the first and second shaftmembers with one another such that the first and second shaft membersare movable relative to one another between a spaced-apart position andan approximated position to move the first and second jaw membersrelative to one another between an open position and a closed position.A ratio of the width of the proximal end of the curved distal section ofeach of the first and second jaw members to the width of the diameter ofthe distal tip portion of each of the first and second jaw members is ina range of from about 1.60 to about 2.00.

In an aspect of the present disclosure, the ratio is in a range of fromabout 1.70 to about 1.90; in another aspect, the ratio is in a range offrom about 1.75 to about 1.85; in yet another aspect, the ratio is about1.80.

In another aspect of the present disclosure, the distal tip portion ofeach of the first and second jaw members defines a half-ellipse, thecurved distal perimeter of each of the first and second jaw membersdefines a half-circumference of the half-ellipse, and the diameter ofeach of the first and second jaw members is a full diameter of thehalf-ellipse.

In still another aspect of the present disclosure, each of the first andsecond jaw members further includes a straight proximal section centeredon the longitudinal axis thereof, the curved distal section extendingfrom the straight proximal section. In aspects, the straight proximalsection defines a length of up to about 0.125 inches.

In another aspect of the present disclosure, the straight proximalsection defines a substantially constant width equal to the width of theproximal end of the curved distal section.

In yet another aspect, the curved distal section of each of the firstand second jaw members defines an angle of curvature of about 15 degreesto about 25 degrees; in aspects, about 17 degrees to about 23 degrees;and, in other aspects, about 19 degrees to about 21 degrees.

Still yet another electrosurgical forceps provided in accordance withaspects of the present disclosure includes first and second shaftmembers and first and second jaw members extending distally from therespective first and second shaft members. Each of the first and secondjaw members includes an opposed, inwardly-facing side having a proximalend and a distal tip portion defined as an area within a concave side ofa curved distal perimeter of the distal tip portion. A pivot couples thefirst and second shaft members with one another such that the first andsecond shaft members are movable relative to one another between aspaced-apart position and an approximated position to move the first andsecond jaw members relative to one another between an open position anda closed position. A ratio of a height of the first and second jawmembers at the proximal ends of the inwardly-facing sides of the firstand second jaw members to a height of the first and second jaw membersat the distal tip portions of the first and second jaw members is in arange of about 1.80 to about 2.10.

In an aspect of the present disclosure, the ratio is in a range of fromabout 1.85 to about 2.05; in another aspect of the present disclosure,the ratio is in a range of from about 1.90 to about 2.00; in stillanother aspect of the present disclosure, the ratio is about 1.94.

In another aspect of the present disclosure, the distal tip portion ofeach of the first and second jaw members defines a half-ellipse with thecurved distal perimeter of each of the first and second jaw membersdefining a half-circumference of the half-ellipse. In such aspects, theheight of the first and second jaw members at the distal tip portionsthereof is measured at a full diameter of the half-ellipse of each ofthe first and second jaw members.

In still another aspect of the present disclosure, a lockboxconfiguration surrounds the pivot and the proximal end of theinwardly-facing side of each of the first and second jaw members isdefined at the point where at least one of the first or second jawmembers extends distally from the lockbox configuration.

In yet another aspect of the present disclosure, each of the first andsecond jaw members is curved along a portion of a length thereof.

Another electrosurgical forceps provided in accordance with aspects ofthe present disclosure includes first and second shaft members and firstand second jaw members extending distally from the respective first andsecond shaft members. Each of the first and second jaw members includesa distal tip portion defined as an area within a concave side of acurved distal perimeter of the distal tip portion. A pivot coupling thefirst and second shaft members with one another such that the first andsecond shaft members are movable relative to one another between aspaced-apart position and an approximated position to move the first andsecond jaw members relative to one another between an open position anda closed position. Each of the first and second jaw members defines astiffness as measured between at least one of: a center of the pivot anda point within the area of the respective jaw member or a proximal endof the respective jaw member to a point within the area of therespective jaw member, of from about 80 lb/in to about 300 lb/in.

In aspects, the stiffness of the first jaw member is from about 80 lb/into about 180 lb/in and/or the stiffness of the second jaw member is fromabout 110 lb/in to about 225 lb/in. The stiffnesses of the jaw membersmay be similar (in embodiments, about the same) or may be different.

In another aspect of the present disclosure, each of the first andsecond jaw members includes an opposed, inwardly-facing surface. In suchaspects, the stiffness of each of the first and second jaw members ismeasured in a direction normal to the respective opposed,inwardly-facing surface thereof.

In yet another aspect of the present disclosure, each of the first andsecond jaw members is curved along a portion of a length thereof.

In still another aspect of the present disclosure, the stiffness of eachof the first and second jaw members is measured in a direction normal toa direction of curvature of the first and second jaw members.

In still yet another aspect of the present disclosure, a lockboxconfiguration surrounds the pivot and the proximal end of theinwardly-facing side of each of the first and second jaw members isdefined at the point where at least one of the first or second jawmembers extends distally from the lockbox configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects and features of the present disclosure are describedhereinbelow with reference to the drawings wherein like numeralsdesignate identical or corresponding elements in each of the severalviews:

FIG. 1 is a side, perspective view of an electrosurgical forcepsprovided in accordance with aspects of the present disclosure;

FIG. 2A is a perspective view from one side of the forceps of FIG. 1with portions of outer housings of first and second shaft membersremoved to illustrate the internal components therein;

FIG. 2B is a perspective view from the other side of the forceps of FIG.1 with other portions of the outer housings of the shaft members removedto illustrate the internal components therein;

FIG. 3A is a perspective view of an inner frame and a jaw member of thefirst shaft member of the forceps of FIG. 1 ;

FIG. 3B is an enlarged, side, perspective view of a distal portion ofthe jaw member of FIG. 3A;

FIG. 3C is perspective view of another body plate of the inner frame andjaw member configured for use with the forceps of FIG. 1 ;

FIG. 4A is a perspective view of an inner frame and a jaw member of thesecond shaft member of the forceps of FIG. 1 ;

FIG. 4B is an enlarged, perspective view of a distal portion of the jawmember of FIG. 4A;

FIG. 5A is a perspective view of a distal portion of the forceps of FIG.1 illustrating the first and second jaw members pivotably coupled toform the end effector assembly;

FIG. 5B is a transverse, cross-sectional view taken along section line“5B-5B” in FIG. 5A;

FIG. 5C is a first perspective view of a pivot member of the endeffector assembly of the forceps of FIG. 1

FIG. 5D is a second perspective view of the pivot member of the endeffector assembly of the forceps of FIG. 1 ;

FIG. 6 is a side, perspective view of the forceps of FIG. 1 withportions removed to illustrate a knife deployment mechanism of theforceps;

FIG. 7 is a rear view of a pair of triggers and a first linkage of theknife deployment mechanism of FIG. 6 ;

FIG. 8 is a side view of a handle of the first shaft member of theforceps of FIG. 1 shown operably coupled to a first linkage of the knifedeployment mechanism of FIG. 6 ;

FIG. 9 is a side view of a knife of the forceps of FIG. 1 ;

FIG. 10 is a perspective view of a distal portion of the knife of FIG. 9;

FIG. 11A is an enlarged, side view of a connector end of one of the pairof triggers configured for use with the knife deployment mechanism ofFIG. 6 ;

FIG. 11B is an enlarged, side view of a portion of the outer housing ofthe first shaft member of the forceps of FIG. 1 including a keyedaperture configured to receive the connector end of the trigger of FIG.11A;

FIGS. 12A and 12B are enlarged, internal views illustrating rotation ofthe connector end of the trigger of FIG. 11A within the keyed apertureof the outer housing of the first shaft member of FIG. 11B;

FIG. 13 is a transverse, cross-sectional view illustrating the pair oftriggers of FIG. 11A engaged with the outer housing of the first shaftmember of FIG. 11B and the knife deployment mechanism of FIG. 6 ;

FIG. 14 is a side view of a proximal portion of the forceps of FIG. 1with portions removed to illustrate a knife lockout of the forceps;

FIG. 15 is a rear view of the forceps of FIG. 1 ;

FIG. 16A is a top, perspective view of a switch assembly of the forcepsof FIG. 1 ;

FIG. 16B is a bottom, perspective view of the switch assembly of FIG.16A;

FIGS. 17A-17H illustrate assembly of the forceps of FIG. 1 in accordancewith the present disclosure;

FIG. 18 is a longitudinal, cross-sectional view of a portion of theforceps of FIG. 1 with components removed to illustrate another knifedeployment mechanism provided in accordance with the present disclosure;

FIG. 19 is a longitudinal, cross-sectional view of a portion of theforceps of FIG. 1 with components removed to illustrate yet anotherknife deployment mechanism provided in accordance with the presentdisclosure;

FIGS. 20A and 20B are respective outer and inner side views of a distalportion of another knife configured for use with the forceps of FIG. 1 ;

FIGS. 21A and 21B are respective outer and inner side views of a distalportion of still another knife configured for use with the forceps ofFIG. 1 ;

FIGS. 22A and 22B are respective outer and inner side views of a distalportion of yet another knife configured for use with the forceps of FIG.1 ;

FIGS. 23A and 23B are respective outer and inner side views of a distalportion of still yet another knife configured for use with the forcepsof FIG. 1 ;

FIGS. 24A and 24B are respective outer and inner side views of a distalportion of another knife configured for use with the forceps of FIG. 1 ;

FIGS. 25A and 25B are respective outer and inner side views of a distalportion of yet another knife configured for use with the forceps of FIG.1 ;

FIG. 26A is an outer side view of a distal portion of another knifeconfigured for use with the forceps of FIG. 1 ;

FIG. 26B is an enlarged view of the area of detail indicated as “26B” inFIG. 26A;

FIG. 27A is an outer side view of a distal portion of still anotherknife configured for use with the forceps of FIG. 1 ;

FIG. 27B is an enlarged, perspective view of a distal end portion ofknife of FIG. 27A; and

FIG. 28 is an enlarged, bottom view of a distal portion of one of thejaw members of the forceps of FIG. 1 ;

FIG. 29 is an enlarged, bottom view of one of the jaw members of theforceps of FIG. 1 ;

FIG. 30 is an enlarged, side view of a distal portion of the forceps ofFIG. 1 ;

and

FIG. 31 is a top view of the tissue-contacting plate of one of the jawmembers of the forceps of FIG. 1 .

DETAILED DESCRIPTION

Referring generally to FIGS. 1-2B, a forceps 100 provided in accordancewith the present disclosure includes first and second shaft members 110,120 each having a proximal end portion 112 a, 122 a and a distal endportion 112 b, 122 b. An end effector assembly 200 of forceps 100includes first and second jaw members 210, 220 extending from distal endportions 112 b, 122 b of shaft members 110, 120, respectively. Forceps100 further includes a pivot member 130 pivotably coupling first andsecond shaft members 110, 120 with one another, a knife 140 (FIGS. 9-10), a knife deployment mechanism 150 for selectively deploying knife 140(FIGS. 9-10 ) relative to end effector assembly 200, a knife lockout 170for inhibiting deployment of knife 140 (FIGS. 9-10 ) prior to sufficientclosure of jaw members 210, 220, and a switch assembly 180 for enablingthe selective supply of electrosurgical energy to end effector assembly100. An electrosurgical cable 300 electrically couples forceps 100 to asource of energy (not shown), e.g., an electrosurgical generator, toenable the supply of electrosurgical energy to jaw members 210, 220 ofend effector assembly 200 upon activation of switch assembly 180.

Continuing with reference to FIGS. 1-2B, each shaft member 110, 120includes an inner frame 114, 124, an outer housing 116, 126 surroundingat least a portion of the respective inner frame 114, 124, and a handle118, 128 engaged with the respective outer housing 116, 126 towardsproximal end portions 112 a, 122 a of shaft members 110, 120,respectively. Inner frames 114, 124 are described in greater detailbelow. Outer housings 116, 126 enclose and/or operably support theinternal components disposed within shaft members 110, 120. Morespecifically, as detailed below, outer housing 116 of shaft member 110encloses and supports at least a portion of inner frame 114, knifedeployment mechanism 150, and lockout 170, while outer housing 126 ofshaft member 120 receives electrosurgical cable 300 and encloses andsupports at least a portion of inner frame 124, switch assembly 180, andthe lead wires 310 of electrosurgical cable 300. Handles 118, 128 areengaged with outer housings 116, 126 towards proximal end portions 112a, 112 b of shaft members 110, 120 and extend outwardly from shaftmembers 110, 120. Handles 118, 128 define finger holes 119, 129configured to facilitate grasping and manipulating shaft members 110,120.

Referring to FIG. 3A, inner frame 114 of shaft member 110 includes abody plate 115 a and a reinforcing plate 115 b attached to body plate115 a, e.g., via welding, to provide increased lateral stiffness andstructural support thereto. In embodiments, reinforcing plate 115 b maybe welded to body plate 115 a in at least two places, e.g., towards theproximal and distal end portions thereof. The increased lateralstiffness provided by reinforcing plate 115 b helps ensure alignment ofdepressible button 183 b (FIG. 16A) of switch assembly 180 with outerhousing 116 of shaft member 110 (Fig. such that depressible button 183 bis depressed and switch assembly 180 activated upon sufficientapproximation of shaft members 110, 120 (see also FIG. 15 ).

Inner frame 114 defines one or more location apertures 115 c, a triggeraperture 115 d, and a longitudinal slot 115 e that each extend throughboth body plate 115 a and reinforcing plate 115 b. The one or morelocation apertures 115 c are configured to receive corresponding posts117 of outer housing 116 to locate and maintain inner frame 114 inposition within outer housing 116. Body plate 115 a extends distallybeyond reinforcing plate 115 b to enable attachment of jaw support 212of jaw member 210 thereto, e.g., via staking or other suitableengagement. The portion of body plate 115 a that extends distally beyondreinforcing plate 115 b further defines a pivot aperture 115 f extendingtransversely therethrough. A stop protrusion 115 g extends from innerframe 114 into pivot aperture 115 f, as detailed below. Body plate 115 aof inner frame 114 further defines a longitudinal channel 115 h orientedtowards reinforcing plate 115 b such that reinforcing plate 115 bencloses a portion of longitudinal channel 115 h.

With additional reference to FIG. 3B, as noted above, jaw support 212 ofjaw member 210 is staked or otherwise engaged, e.g., welded, press-fit,mechanically locked, etc., to the portion of body plate 115 a thatextends distally beyond reinforcing plate 115 b. Jaw member 210 furtherincludes an electrically-conductive, tissue-contacting plate 214 and aninsulative housing 216. Tissue-contacting plate 214 defines alongitudinally-extending knife channel 215 a extending at leastpartially therethrough and may include one or more stop members 215 bdisposed thereon and electrically isolated therefrom. Insulative housing216 of jaw member 210 is overmolded or otherwise secured about a portionof jaw support 212, tissue-contacting plate 214, and body plate 115 a ofinner frame 114 of shaft member 110. Insulative housing 216 includes adistal portion 217 a and a proximal extension portion 217 b. Proximalextension portion 217 b of insulative housing 216 is configured toextend proximally along body plate 115 a of inner frame 114 to (orproximally beyond) pivot aperture 115 f thereof. The electrical lead 310(FIGS. 2A and 3B) configured to electrically couple to tissue-contactingplate 214 is captured between body plate 115 a and proximal extensionportion 217 b of insulative housing 216 to protect and facilitaterouting of the electrical lead 310 (FIGS. 2A and 3B) from shaft member120, around pivot aperture 115 f, and distally therefrom to electricallycouple to tissue-contacting plate 214.

Distal portion 217 a of insulative housing 216 of jaw member 210 extendsabout the periphery of tissue-contacting plate 214 and defines a mainsection 218 a, a raised section 218 b, and a beak section 218 c. Mainsection 218 a of distal portion 217 a of insulative housing 216 extendson either side of tissue-contacting plate 214 and is offset relativethereto such that tissue-contacting plate 214 is raised relative to mainsection 218 a. Raised section 218 b of distal portion 217 a ofinsulative housing 216 extends distally from main section 218 a oneither side of tissue-contacting plate 214 and is still recessedrelative to tissue-contacting plate 214 but is closer to being co-planarwith tissue-contacting plate 214 as compared to main section 218 a. Beaksection 218 c of distal portion 217 a of insulative housing 216 isdisposed distally of tissue-contacting plate 214 and extends to orbeyond tissue-contacting plate 214. Beak section 218 c inhibits tissuefrom entering the area between jaw members 210, 220 of end effectorassembly 200 when end effector assembly 200 is disposed in the closedposition and utilized for blunt dissection (see FIG. 5A).

Referring to FIG. 3C, another embodiment is provided wherein body plate115 a′ of inner frame 114′ does not define the pivot aperturetherethrough but, rather, terminates proximally of the pivot location.In this embodiment, jaw support 212′ of jaw member 210′ defines pivotaperture 115 f and extends from the distal body portion of jaw member210′ proximally beyond the pivot location to enable jaw support 212′ tobe staked or otherwise engaged to body plate 115 a′ of inner frame 114′proximally of the pivot location. Pivot aperture 115 f′ defined withinjaw support 212′ receives pivot member 130 similarly as detailed abovewith regard to pivot aperture 115 f (se FIGS. 3A and 5C). In thisembodiment, jaw support 212′ may include, in the areas where jaw support212′ replaces body plate 115 a (FIG. 3A), any of the features of bodyplate 115 a of inner frame 114 (see FIG. 3A) and may likewise includeany of the features of jaw support 212 (FIG. 3A).

Continuing with reference to FIG. 3C, in embodiments, the jaw support,e.g., jaw support 212′, may further define a notch 115 i′ configured toreceive an edge 125 g (FIG. 17B) of distal clevis portion 125 c of innerframe 124 of shaft member 120 (FIG. 4A) therein to define thespaced-apart position of shaft members 110, 120 (see FIGS. 2A-2B). Thatis, receipt of edge 125 g (FIG. 17B) within notch 115 i′ inhibitsfurther movement of shaft members 110, 120 apart from one another, thusdefining the furthest spaced-apart portion of shaft member 110, 120 (seeFIGS. 2A-2B).

Turning to FIG. 4A, inner frame 124 of shaft member 120 includes anelongated body portion 125 a, an enlarged proximal portion 125 b, and adistal clevis portion 125 c. Enlarged proximal portion 125 b of innerframe 124 provides additional structural support to shaft member 120 anddefines one or more location apertures 125 d that, similarly as withlocation apertures 115 c of inner frame 114 of shaft member 110 (FIG.3A), are configured to receive corresponding posts 127 of outer housing126 to locate and maintain inner frame 124 in position within outerhousing 126. Elongated body portion 125 a of inner frame 124 extendsthrough outer housing 126 of shaft member 120, while distal clevisportion 125 c of shaft member 120 extends distally from outer housing126. Distal clevis portion 125 c may be welded to, monolithically formedwith, or otherwise engaged to elongated body portion 125 a of innerframe 124. Distal clevis portion 125 c of inner frame 124 is detailedbelow.

Elongated body portion 125 a defines a flexibility, e.g., is flexible anamount according to a spring constant thereof, thus enabling flexure ofelongated body portion 125 a in response to application of a jaw forceat jaw member 220. This configuration enables the application of a jawforce within a particular range, e.g., between about 3 kg/cm² and about16 kg/cm², when shaft members 110, 120 are disposed in the approximatedposition corresponding to the closed position of jaw members 210, 220.Referring also to FIGS. 3A, 3B, and 4B, in embodiments, in addition tothe flexion of elongated body portion 125 a providing a jaw force withina particular range, flexion of the jaw members 210, 220 may alsocontribute to providing a jaw force within a particular range. Morespecifically, due to the relatively fine configuration of the jawmembers 210, 220 and the fact that the jaw members 210, 220 taper inheight and width from the proximal ends to the distal ends thereof, thejaw members 210, 220 themselves provide flexibility that, in conjunctionwith the flexibility of elongated body portion 125 a, provide a jawforce within a particular range to facilitate tissue treatment.

Referring to FIGS. 4A and 4B, jaw member 220 of end effector assembly200 is supported on a distal extension (not shown) of distal clevisportion 125 c of inner frame 124 of shaft member 120. The distalextension (not shown) of distal clevis portion 125 c of inner frame 124serves as the jaw frame of jaw member 220. Jaw member 220 furtherincludes an electrically-conductive, tissue-contacting plate 224 and aninsulative housing 226. Tissue-contacting plate 224 defines alongitudinally-extending knife channel 225 extending at least partiallytherethrough and may include one or more stop members, similarly as withjaw member 210 (FIG. 3B). Insulative housing 226 of jaw member 220 issimilar to that of jaw member 210 (FIG. 3B) and, thus, the featuresthereof will not be repeated here.

As illustrated in FIGS. 1 and 3A-4B, jaw members 210, 220 taper inheight and width from the proximal ends to the distal ends thereof, thusfacilitating blunt dissection and inhibiting jaw splay. Jaw members 210,220 also define curved configurations that facilitate visualization ofthe surgical site and provide increased surface area for graspingtissue.

With reference to FIGS. 5A-5B, distal clevis portion 125 c of innerframe 124 of shaft member 120 and body plate 115 a of inner frame 114 ofshaft member 110 are pivotably coupled to one another via pivot member130 such that shaft members 110, 120 are movable relative to one anotherbetween spaced-apart and approximated positions to thereby pivot jawmembers 210, 220 relative to one another between open and closedpositions. More specifically, distal clevis portion 125 c and body plate115 a define a lock-box configuration wherein distal clevis portion 125c includes a bifurcated, U-shaped configuration having an elongated slotdefined therein, and wherein body plate 115 a is configured for nestedreceipt within the elongated slot of the bifurcated, U-shaped distalclevis portion 125 c. Referring in particular to FIG. 5B, sufficientclearance is provided between distal clevis portion 125 c and body plate115 a when body plate 115 a is nested within distal clevis portion 125 csuch that lead wires 310 are permitted to extend therethrough,ultimately to electrically couple tissue-contacting plates 214, 224(FIGS. 3B and 4B, respectively) to switch assembly 180 (FIGS. 1-2B) andthe source of energy (not shown). Further, body 172 of knife lockout 170is configured for positioning adjacent body plate 115 a within distalclevis portion 125 c to minimize lateral play between body plate 115 aand distal clevis portion 125 c and to act as a wire guide to maintainthe lead wires 310 for jaw member 210 distally spaced-apart from pivotmember 130. With respect to acting as a wire guide, body 172 of knifelockout 170 inhibits the lead wire 310 for jaw member 210 frominterfering with and being damaged during the pivoting of shaft members110, 120 about pivot member 130, and inhibits the lead wire 310 for jawmember 210 from interfering with and being damaged by translation ofknife 140.

Referring also to FIGS. 5C-5D, pivot member 130 includes a body 132 anda cap 134. Body 132 of pivot member 130 is configured to extend throughan aperture 125 e defined through one of the side walls of distal clevisportion 125 c of inner frame 124 of shaft member 120, pivot aperture 115f of body plate 115 a of inner frame 114 of shaft member 110, and into akeyed aperture (or apertures) 125 f defined through the other side wallof distal clevis portion 125 c in fixed rotational orientation relativethereto. Body portion 132 of pivot member 130 is configured to be weldedto the portion of the side wall of distal clevis portion 125 c thatsurrounds keyed aperture(s) 125 f. More specifically, the keying of bodyportion 132 within keyed aperture(s) 125 f maintains proper orientationof pivot member 130 during welding. Body 132 is further configured toabut stop protrusion 115 g (FIG. 3A) upon pivoting of shaft members 110,120 away from one another to define a furthest-spaced apart position ofshaft members 110, 120 and, similarly, a most-open position of jawmembers 210, 220. A slot 136 defined through body 132 of pivot member130 is configured to permit translation of knife 140 (FIGS. 9-10 )therethrough, as detailed below.

Cap 134 of pivot member 130 defines a location recess 134′ therein, asillustrated in FIG. 5C, for example, although other configurations arealso contemplated. Location recess 134′ is described below with respectto the assembly of forceps 100.

Turning to FIGS. 1 and 6-8 , knife deployment mechanism 150 is coupledto shaft member 110 and generally includes a pair of opposed triggers152 extending from either side of shaft member 110, first and secondlinkages 154, 156, and a biasing spring 158. Knife deployment mechanism150 is disposed within outer housing 116 of shaft member 110 with theexception of opposed triggers 152 which extend from either side of outerhousing 116. First linkage 154 is configured for positioning on one sideof inner frame 114 of shaft member 110 and includes a pair of integral(or otherwise engaged) pivot bosses 161 extending from either sidethereof at a first end portion of first linkage 154. One of the pivotbosses 161 extends through trigger aperture 115 d of inner frame 114(see FIG. 3A). Each pivot boss 161 extends through an aperture definedthrough outer housing 116 of shaft member 110 to enable engagement ofopposed triggers 152 therewith on either side of shaft member 110, e.g.,via press-fitting, adhesion, or other suitable engagement.

Referring to FIGS. 6-8 , a proximal end portion of second linkage 156 ispivotably coupled to first linkage 154 at a second end portion of firstlinkage 154. However, greater or fewer linkages 154, 156 are alsocontemplated. A distal end portion of second linkage 156 is pivotablycoupled to knife 140 (see also FIGS. 9-10 ) via a pivot pin 163. Pivotpin 163 may be integrally formed with second linkage 156, e.g., as apost extending therefrom, or may be a separate component from secondlinkage 156. Pivot pin 163 extends transversely through longitudinalslot 115 e of inner frame 114 of shaft member 114 such that pivot pin163 is constrained to longitudinal movement within longitudinal slot 115e. Second linkage 156 is disposed on one side of inner frame 114, whichmay be the same side as first linkage 154 or the opposite side (asshown). In either configuration, pivot pin 163 extends from secondlinkage 156 and through longitudinal slot 115 e such that a portion ofpivot pin 163 protrudes laterally from the opposite side of inner frame114.

Biasing spring 158 may be configured as an extension spring or othersuitable biasing spring 158 and is engaged at a distal end portionthereof to first linkage 154 and at a proximal end portion thereof to asupport plate 166. Support plate 166 includes handle 118 of shaft member110 integrally formed therewith or otherwise engaged thereto, and may besecured within outer housing 116 in any suitable fashion, e.g., viaprotrusion-aperture engagement. Support plate 166 provides increasedstructural support to shaft member 110 to inhibit splaying of shaftmembers 110, 120 during use. Shaft member 120 similarly includes asupport plate 168 integrally formed with or otherwise engaging handle128 of shaft member 120 and secured to outer housing 126, althoughsupport plate 168 need not extend distally as with support plate 166(see FIGS. 2A and 2B).

Biasing spring 158 biases first linkage 154 towards a first orientation,corresponding to the un-actuated position of triggers 152 and theproximal-most position of second linkage 156, thereby biasing knife 140towards the retracted position. Upon rotation of either of triggers 152relative to shaft member 110, first linkage 154 is rotated against thebias of biasing spring 158 to thereby urge second linkage 156 distallysuch that pivot pin 163 is driven distally though longitudinal slot 115e to urge knife 140 from the retracted position towards an extendedposition, wherein knife 140 extends through slot 136 of pivot member 130and channels 215 a, 225 of jaw members 210, 220 (FIGS. 3B and 4B,respectively).

With reference to FIG. 18 , another knife deployment mechanism 1150configured for use with forceps 10 (FIG. 1 ) is shown. To the extentconsistent, and except as specifically contradicted below, knifedeployment mechanism 1150 may include any of the features of knifedeployment mechanism 150, and vice versa. Knife deployment mechanism1150 includes a pair of opposed triggers (not shown) extending fromeither side of shaft member 110, first, second, and third linkages 1154,1155, 1156, respectively, and a biasing spring 1158.

Knife deployment mechanism 1150 is disposed within outer housing 116 ofshaft member 110 with the exception of the opposed triggers which extendfrom either side of outer housing 116. First linkage 1154 is configuredfor positioning on one side of inner frame 114 of shaft member 110 andincludes a pair of integral (or otherwise engaged) pivot bosses 1161extending from either side thereof at a first end portion of firstlinkage 1154. One of the pivot bosses 1161 extends through inner frame114 and each pivot boss 1161 extends through an aperture defined throughouter housing 116 of shaft member 110 to enable engagement of theopposed triggers thereon.

A proximal end portion of second linkage 1155 is pivotably coupled tofirst linkage 1154 at a second end portion of first linkage 1154 and adistal end portion of second linkage 1155 is pivotably coupled to aproximal end portion of third linkage 1156 via a pivot pin 1159. Eitheror both ends of pivot pin 1159 are received within an arcuate track 1160defined on the interior surface of either or both sides of outer housing116. Third linkage 1156 is pivotably coupled to knife 140 at a distalend of third linkage 1156.

Biasing spring 1158 may be configured as an extension spring and isengaged at a distal end portion thereof to first linkage 1154 and isfixed within shaft member 110 at a proximal end portion thereof so as tobias first linkage 1154 towards a first orientation, corresponding tothe un-actuated position of the triggers and the proximal-most positionof second and third linkages 1155, 1156, thereby biasing knife 140towards the retracted position.

Upon rotation of either of the triggers relative to shaft member 110,first linkage 1154 is rotated against the bias of biasing spring 1158 tothereby urge second linkage 1556 distally (urging pivot pin 1159distally through arcuate track 1160) to thereby urge third linkage 1156distally such knife 140 is driven distally from the retracted positiontowards the extended position.

With reference to FIG. 19 , yet another knife deployment mechanism 2150configured for use with forceps 10 (FIG. 1 ) is shown. To the extentconsistent, and except as specifically contradicted below, knifedeployment mechanism 2150 may include any of the features of knifedeployment mechanism 150, and vice versa. Knife deployment mechanism2150 includes a pair of opposed triggers 2152 (only one of which isshown in FIG. 19 ) extending from either side of shaft member 110, firstsecond, and third linkages 2154, 2155, 2156, respectively, and a biasingspring (not shown).

Knife deployment mechanism 2150 is disposed within outer housing 116 ofshaft member 110 with the exception of opposed triggers 2152 whichextend from either side of outer housing 116. First linkage 2154includes a pair of integral (or otherwise engaged) pivot bosses 2161extending from either side thereof at a first end portion of firstlinkage 2154. Pivot bosses 2161 extend through apertures defined throughouter housing 116 of shaft member 110 to enable engagement of opposedtriggers 2152 thereon.

A proximal end portion of second linkage 2155 is coupled to firstlinkage 2154 at a second end portion of first linkage 2154 via apin-slot engagement 2159. A distal end portion of second linkage 2155 ispivotably coupled to a proximal end portion of third linkage 2156. Thirdlinkage 2156 is pivotably coupled to knife 140 at a distal end of thirdlinkage 2156. The biasing spring is configured to bias first linkage2154 towards a first orientation, corresponding to the un-actuatedposition of triggers 2152 and the proximal-most position of second andthird linkages 2155, 2156, thereby biasing knife 140 towards theretracted position.

Upon rotation of either of triggers 2152 relative to shaft member 110,first linkage 2154 is rotated against the bias of the biasing spring tothereby urge second linkage 2155 distally (as the pin of pin-slotengagement 2159 is pivoted and slid through the slot of pin-slotengagement 2159), to thereby urge third linkage 1156 distally such knife140 is driven distally from the retracted position towards the extendedposition.

Referring generally to FIGS. 18 and 19 , knife deployment mechanisms1150, 2150 are advantageous in that, by utilizing three linkages in theconfigurations detailed above, they allow for a reduced height of shaftmember 110, thus facilitating a surgeon's visualization into thesurgical site.

Referring to FIGS. 9 and 10 , knife 140 includes a proximal body 142defining an aperture 144 through which knife 140 is pivotably coupled tosecond linkage 156 of knife deployment mechanism 150 via pin 163 (seeFIG. 6 ). Proximal body 142 is slidably disposed within channel 115 hbetween body plate 115 a and reinforcing plate 115 b of inner frame 114of shaft member 110 (see FIG. 3A). Knife 140 further includes a distalbody 146 defining a lower profile as compared to proximal body 142 andextending distally from proximal body 142. Distal body 146 defines adistal cutting portion 148. Distal cutting portion 148 defines anenlarged height as compared to distal body 146 and may be etched todefine an asymmetrically sharpened configuration wherein one side ofdistal cutting portion 148 extends further distally than the oppositeside (due to the removal of material from the opposite side during theetching process). The enlarged height of distal cutting portion 148helps ensure that distal cutting portion 148 extends fully through thegap defined between jaw members 210, 220 (FIG. 1 ) and is at leastpartially received in respective knife channels 215 a, 225 thereof (seeFIGS. 3B and 4B). In the retracted position of knife 140, the enlargedheight of distal cutting portion 148 is configured for receipt within aroof 213 defined by a proximally-extending portion of jaw support 212 ofjaw member 210 (see FIG. 3A). The etched distal cutting edge of distalcutting portion 148 defines three segments: a main cutting segment 149a, a lower cutting segment 149 b extending from one end of main cuttingsegment 149 a at an angle relative thereto, and an upper cutting segment149 c extending from the opposite end of main cutting segment 149 a atan angle relative thereto.

Knife 140 further includes a partial etch 149 d extending along aportion of distal body 146 and distal cutting portion 148 of knife 140.Partial etch 149 d may extend along either or both sides of knife 140.Partial etch 149 d is configured to inhibit wear of knife 140, topromote flexibility to facilitate translation of knife 140 through knifechannels 215 a, 225 of jaw members 210, 220 (see FIGS. 3A-4B), tofacilitate smooth translation of knife 140 through knife channels 215 a,225 (see FIGS. 3A-4B) should partial etch 149 d come in contact with thesidewalls defining channels 215 a, 225 (see FIGS. 3A-4B), and to providegreater clearance between knife 140 and the sidewalls defining channels215 a, 225 (see FIGS. 3A-4B).

In use, distal body 146 of knife 140 is configured to reciprocatethrough slot 136 of pivot member 130 (FIG. 5D) to translate distalcutting edge 148 through knife channels 215 a, 225 of jaw members 210,220 in response to actuation of either of triggers 152 (see FIGS.2A-4B). Knife 140 further includes a stop shoulder 147 defined at thetransition between proximal body 142 and distal body 146. Stop shoulder147 defines a height greater than a height of slot 136 of pivot member130 (FIG. 5D) such that stop shoulder 147 is inhibited from passingtherethrough. Accordingly, stop shoulder 147 defines the distal-mostextent of travel of knife 140, e.g., wherein stop shoulder 147 abutspivot member 130 (FIG. 5D). Alternatively, rather than abutting pivotmember 130, stop shoulder 147 may abut a portion of distal clevisportion 125 c defining keyed aperture(s) 125 f for similar purposes.

Referring to FIGS. 20A-25B, knives 1140, 2140, 3140, 4140, 5140, 6140having various different configurations of the distal body 1146, 2146,3146, 4146, 5146, 6146, respectively, are illustrated and detailedbelow. Knives 1140, 2140, 3140, 4140, 5140, 6140, more specifically, areconfigured to promote flexibility to facilitate translation through thecurved knife channels 215 a, 225 of curved jaw members 210, 220 (seeFIGS. 3A-4B) and to inhibit contact with, wear of, and damage tochannels 215 a, 225 (see FIGS. 3A-4B) and knives 1140, 2140, 3140, 4140,5140, 6140. The distal body 1146, 2146, 3146, 4146, 5146, 6146 of eachknife 1140, 2140, 3140, 4140, 5140, 6140 defines a respective outer sidesurface 1147 a, 2147 a, 3147 a, 4147 a, 5147 a, 6147 a (e.g., the sideson the outside of the curve through which the knives travel, facing theconcave sides of the knife channels) and a respective inner side surface1147 b, 2147 b, 3147 b, 4147 b, 5147 b, 6147 b (e.g., the sides on theinside of the curve through which the knives travel, facing the convexsides of the knife channels). To the extent consistent, any of thefeatures of 1140, 2140, 3140, 4140, 5140, 6140 may be used inconjunction with one another in any suitable combination.

Distal body 1146 of knife 1140, as illustrated in FIGS. 20A and 20B,includes outer side surface 1147 a and inner side surface 1147 b. Innerside surface 1147 b is flat (within manufacturing tolerances), asillustrated in FIG. 20B. Outer side surface 1147 a includes a firstetching forming an etched distal cutting edge 1148, similarly asdetailed above with respect to knife 140 (FIGS. 9 and 10 ). Outer sidesurface 1147 a further includes a second, partial etching 1149 such thatouter side surface 1147 a includes a relatively protruded surfaceportion 1149 a and a relatively recessed surface portion 1149 b. As aresult of the second, partial etching 1149, the relatively protrudedsurface portion 1149 a includes a tapered proximal section that tapersdown in height from the full height of body 1146 of knife 1140 in aproximal-to-distal direction, and a constant height (withinmanufacturing tolerances) distal section extending from the distal endof the tapered proximal section. The constant height distal section ofthe relatively protruded surface portion 1149 a extends to the distalcutting portion of knife 1140 but remains spaced from etched distalcutting edge 1148. The distal end of the constant height section of therelatively protruded surface portion 1149 a is rounded to eliminatesharp edges.

Distal bodies 2146, 3146 of knives 2140, 3140 (FIGS. 21A-21B and22A-22B, respectively), are similar to distal body 1146 of knife 1140.The second, partial etches 2149, 3149 may be configured such thatrelatively protruded surface portions 2149 a, 3149 a define differenttapered proximal portion lengths, different tapered proximal portionslopes, different constant height distal portion lengths, and/ordifferent constant height distal portion heights as compared to those ofdistal body 1146 of knife 1140. Further, outer side surface 2147 a ofdistal body 2146 of knife 2140 includes a laser-polished tip portion2148. The first etching of distal body 3146 of knife 3140, on the otherhand, defines a sharpened point 3148 b within distal cutting edge 3148a.

Referring to FIGS. 23A-23B, distal body 4146 of knife 4140 includesouter and inner side surfaces 4147 a, 4147 b, which include second,partial etchings 4149 a, 4149 b of generally similar configuration. Forexample, outer side surface 4147 a defines second, partial etching 4149a such that the relatively protruded surface portion thereof defines aU-shaped configuration oriented such that the uprights of the U-shapeextend longitudinally, the closed end of the U-shape is disposedproximally, and the open end of the U-shape is disposed distally. Innerside surface 4147 b defines second, partial etching 4149 b such that therelatively protruded surface portion thereof defines a U-shapedconfiguration oriented such that the uprights of the U-shape extendlongitudinally, the closed end of the U-shape is disposed proximally,and the open end of the U-shape is disposed distally. However, second,partial etching 4149 a stops before reaching the distal cutting portionof knife 4140, while second partial etching 4149 b extends about anouter perimeter of the distal cutting portion of knife 4140, surroundinga relatively protruded surface portion peninsula at the distal cuttingportion of knife 4140. Distal cutting edge 4148, formed via a firstetching on outer side surface 4147 a, may further include a steppedportion to define a radiused (or more radiused) lower distal corner ofdistal cutting edge 4148. In other embodiments, the lower distal cornerof distal cutting edge 4148 is radiused without a stepped portion.Alternatively, rather than a radiused lower distal corner, the distalcutting edge may meet a flat lower edge, such as illustrated in FIGS.20A, 21A, and 25A.

Referring to FIGS. 24A-24B, distal body 5146 of knife 5140 includesouter and inner side surfaces 5147 a, 5147 b, which include second,partial etchings 5149 a, 5149 b of generally similar configuration. Forexample, outer side surface 5147 a defines second, partial etching 5149a wherein the relatively protruded surface portion includes a taperedproximal section that tapers down in height in a proximal-to-distaldirection, and a constant height (within manufacturing tolerances)distal section extending from the distal end of the tapered proximalsection and terminating at the distal cutting portion of knife 5140 butspaced-apart from the distal cutting edge thereof. Inner side surface5147 b defines second, partial etching 5149 b wherein the relativelyprotruded surface portion includes a tapered proximal section thattapers down in height in a proximal-to-distal direction, and a constantheight (within manufacturing tolerances) distal section extending to thedistal cutting portion of knife 5140. However, second, partial etching5149 b is fully etched at the distal cutting portion of knife 5140,rather than terminating at the distal cutting portion spaced-apart fromthe distal cutting edge.

FIGS. 25A and 25B illustrate knife 6140 including distal body 6146having outer and inner side surfaces 6147 a, 6147 b, which includesecond, partial etchings 6149 a, 6149 b. Second partial etchings 6149 a,6149 b similarly extend along a distal portion of distal body 6146, theentire height thereof, except that inner side surface 6147 a includes adistal portion that is not etched, so as to define a relativelyprotruded surface portion 6149 c that opposes and is shaped similarly todistal cutting edge 6148, which is etched at the distal end of outerside surface 6147 a.

Referring to FIGS. 26A and 26B, a distal portion 7146 of another knife7140 configured to promote flexibility to facilitate translation throughthe curved knife channels 215 a, 225 of curved jaw members 210, 220 (seeFIGS. 3A-4B) and to inhibit contact with, wear of, and damage tochannels 215 a, 225 (see FIGS. 3A-4B) and knife 7140 is shown. Knife7140 may include any of the features of any of the knives detailedabove. Distal portion 7146 of knife 7140 further includes a plurality oftransverse apertures 7147 extending therethrough. Apertures 7147 arespaced-apart along at least a portion of the length of distal portion7146 of knife 7140. Apertures 7147 increase the flexibility of distalportion 7146 of knife 7140, thus facilitating translation of knife 7140through the curved knife channels 215 a, 225 of curved jaw members 210,220 (see FIGS. 3A-4B).

Turning to FIGS. 27A and 27B, a distal portion 8146 of another knife8140 configured to promote flexibility to facilitate translation throughthe curved knife channels 215 a, 225 of curved jaw members 210, 220 (seeFIGS. 3A-4B) and to inhibit contact with, wear of, and damage tochannels 215 a, 225 (see FIGS. 3A-4B) and knife 8140 is shown. Distalportion 8146 includes an outer side surface 8147 a and inner sidesurface 8147 b. Inner side surface 8147 b is flat (within manufacturingtolerances), although other configurations are also contemplated. Outerside surface 8147 a includes a first etching forming an etched distalcutting edge 8148, similarly as detailed above with respect to knife 140(FIGS. 9 and 10 ). Outer side surface 8147 a further includes a second,partial etching 8149 forming a plurality of alternating relativelyprotruded surface strips 8149 a and relatively recessed surface strips8149 b along at least a portion of the length of distal portion 8146.Second, partial etching 8149 thus forms alternating relatively thickerand thinner sections of distal portion 8146 along at least a portion ofthe length of distal portion 8146, which increases the flexibility ofdistal portion 8146 of knife 8140, thus facilitating translation ofknife 8140 through the curved knife channels 215 a, 225 of curved jawmembers 210, 220 (see FIGS. 3A-4B).

With momentary reference to FIGS. 1 and 2A, knife deployment mechanism150 is operably positioned on shaft member 110 and relative to shaftmember 120 such that such that triggers 152 do not extend beyond theheight dimension of forceps 100 in the vicinity of triggers 152, even inthe furthest-approximated position of shaft members 110, 120. As aresult of this configuration, forceps 100 benefits from a low-profiledesign that inhibits triggers 152 from catching on the surgeon, patient,or on nearby objections during use and/or as forceps 100 is inserted andwithdrawn from the surgical site.

Referring to FIGS. 11A-13 , in some embodiments, each trigger 152′ maybe provided with a non-circular aperture 153 a′ configured to receive acorrespondingly-shaped pivot boss (not shown) of first linkage 154′(FIG. 13 ). In such embodiments, each trigger 152′ may further include apair of opposed cantilever arms 153 b′ extending from opposite sides ofnon-circular aperture 153 a′. As detailed below, cantilever arms 153 b′include fingers 153 c′ configured to operably engage outer housing 116′to retain triggers 152′ in engagement with first linkage 154′ (FIG. 13 )without the need for press-fitting.

With reference to FIG. 11B, in order to operably engage triggers 152′,outer housing 116′ defines a pair of opposed apertures 118′ (only one ofwhich is shown) defining a pair of cut-outs 119 a′. Outer housing 116′further includes a stop protrusion 119 b′ on an inner surface thereofadjacent each cut-out 119 a′.

Referring to FIGS. 12A and 12B, in order to engage triggers 152′ withouter housing 116′, triggers 152′ are oriented such that non-circularapertures 153 a′ are aligned relative to the correspondingly-shapedpivot bosses (not shown) and such that cantilever arms 153 b′ arealigned relative to cut-outs 119 a′. Thereafter, triggers 152′ areadvanced such that the pivot bosses (not shown) are received withinnon-circular apertures 153 a′ and such that cantilever arms 153 b′extend sufficiently through cut-outs 119 a′ and into outer housing 116′such that fingers 153 c′ are disposed internally of outer housing 116′.Once this position has been achieved, triggers 152′ are rotated relativeto outer housing 126 such that fingers 153 c′ are no longer aligned withcut-outs 129 a′ and, accordingly, such that triggers 152′ are inhibitedfrom backing out of apertures 128′. Thereafter, first linkage 154′ iscoupled to the other components of the knife deployment mechanism, e.g.,similarly as detailed above. This engagement of first linkage 154′ withthe other components defines a range of motion of first linkage 154′and, more specifically, limits the range of motion thereof such that, inconjunction with stop protrusions 119 b′, first linkage 154′ inhibitstriggers 152′ from rotating back to a position wherein cantilever arms153 b′ are aligned relative to cut-outs 119 a′. Thus, disengagement oftriggers 152′ from outer housing 116′ and first linkage 154′ areinhibited without requiring press-fit, adhesion, or otherbackout-preventing engagement between triggers 152′ and first linkage154′.

Turning to FIGS. 1, 2A, and 14 , knife lockout 170 works in conjunctionwith shaft members 110, 120 to inhibit deployment of knife 140 prior toshaft members 110, 120 reaching a sufficiently-approximated positioncorresponding to a sufficiently-closed position of jaw members 210, 220.Knife lockout 170 includes a body 172 that is disposed about a portionof the inner frame 114 of shaft member 110 and forms a portion of outerhousing 116 of shaft member 110. More specifically, as shown in FIG. 1 ,body 172 of knife lockout 170 defines a complementarily-shaped abuttingsurface with the abutting surface of the adjacent other component(s) ofhousing 116 such that housing 116 defines a substantially continuousouter surface. Body 172 extends at least partially within U-shapeddistal clevis portion 125 c of shaft member 110 to inhibit excesslateral play therebetween, as noted above.

Referring to FIG. 14 , knife lockout 170 further includes a cantileverarm 174 extending proximally from body 172. Cantilever arm 174 and body172 may be integrally formed, e.g., via injection molding, or may beattached in any other suitable fashion. Cantilever arm 174 extends alonginner frame 114 of shaft member 110 on an opposite side of inner frame114 as compared to second linkage 156 of knife deployment mechanism 150.Cantilever arm 174 defines a relatively narrowed configuration to permitflexing of cantilever arm 174. A finger 176 integrally formed withcantilever arm 174 extends generally perpendicularly from a free end ofcantilever arm 174 and through an opening defined in outer housing 116of shaft member 110 towards shaft member 120. A nook 178 is defined atthe junction of cantilever arm 174 and finger 176. A stop 179 protrudesfrom cantilever arm 174 in the vicinity of nook 178 and defines anangled distal wall 179 a and a vertical proximal wall 179 b that,together with cantilever arm 174 and finger 176, enclose a portion ofnook 178.

With shaft members 110, 120 sufficiently spaced-apart from one another,finger 176 of knife lockout 170 is spaced-apart from outer housing 126of shaft member 120 such that cantilever arm 174 is disposed in itsat-rest position. In the at-rest position, cantilever arm 174 extendsalong and in generally parallel orientation relative to longitudinalslot 115 e of inner frame 114 of shaft member 110. Further, nook 178 isdisposed at the proximal end of longitudinal slot 115 e and receives theportion of pivot pin 163 that extends from second linkage 156 throughlongitudinal slot 115 e therein. As such, vertical proximal wall 179 bof stop 179 inhibits distal advancement of pivot pin 163 in the at-restposition of cantilever arm 174 and, accordingly, inhibits deployment ofknife 140.

In order to disengage knife lockout 170 to permit deployment of knife140, shaft members 110, 120 are sufficiently approximated such that aportion of outer housing 126 of shaft member 120 contacts finger 176 ofknife lockout 170 and urges finger 176 further into housing 116 of shaftmember 110. As finger 176 is urged further into housing 116, cantileverarm 174 is flexed such that nook 178 is withdrawn from about pivot pin163 and vertical proximal wall 179 b of stop 179 is removed from thepath of pivot pin 163. Once this has been achieved, knife deploymentmechanism 150 may be actuated, as detailed above, to advance pivot pin163 distally through slot 115 e to deploy knife 140 from the retractedposition towards the extended position.

Should shaft members 110, 120 be moved apart from one anothersufficiently such that shaft member 120 no longer urges finger 176 toflex cantilever arm 174, cantilever arm 174 is resiliently returned toits at-rest position. If knife 140 is disposed in the retracted positionat this point, nook 178 is returned to surrounding engagement aboutpivot pin 163. However, if knife 140 is disposed in the deployedposition or a partially-deployed position, the return of cantilever arm174 to its at-rest position does not re-capture pivot pin 163. Rather,upon subsequent return of knife 140 to the retracted position, pivot pin163 is moved proximally and into contact with angled distal wall 179 aof stop 179, camming therealong and urging cantilever arm 174 to flexfrom the at-rest position sufficiently so as to enable pivot pin 163 toreturn to the proximal end of longitudinal slot 115 e. Once pivot pin163 reaches this position, cantilever arm 174 is returned to the at-restposition and, as a result, nook 178 is returned to surroundingengagement about pivot pin 163, thereby locking-out knife 140 untilshaft members 110, 120 are once again sufficiently approximated. Thebiasing force of biasing member 158 is sufficient to move pivot pin 163proximally to deflect cantilever arm 174 and reset knife lockout 170 asdetailed above. As such, resetting of knife lockout 170 occursautomatically (if shaft members 110, 120 are sufficiently spaced-apart)upon return of knife 140 to the retracted position.

With reference to FIGS. 2A, 3B, 3A, 4A, and 15 , the above-detailedstructural support features of shaft members 110, 120 inhibit splayingof shaft members 110, 120 during use, e.g., in the directions of arrows“S” (FIG. 15 ). More specifically, reinforcing plate 115 b of innerframe 114, enlarged body portion 125 a of inner frame 124, supportplates 166, 168 (that retain handles 118, 128), and the lockboxconfiguration of shaft members 110, 120 all add structural support toshaft members 110, 120 to inhibit splaying of shaft members 110, 120during use. Further, the positioning of knife 140 within channel 115 hbetween body plate 115 a and reinforcing plate 115 b inhibits splay ofknife 140 during use.

Turning to FIGS. 16A and 16B, switch assembly 180 is disposed on shaftmember 120 and generally includes an activation button 182 and a PrintedCircuit Board (PCB) 184. Activation button 182 includes a button housing183 a and a depressible button 183 b. Depressible button 183 b isconfigured to be contacted by the outer housing 116 of shaft member 110upon sufficient approximation of shaft members 110, 120 so as to depressdepressible button 183 b and activate switch assembly 180. Withadditional reference to FIGS. 1-2B, as noted above, the position ofshaft members 110, 120 wherein switch assembly 180 is activated,together with the flexion of inner frame 124, enable application of aparticular jaw force, or jaw force within a particular range, to tissuegrasped between jaw members 210, 220.

PCB 184 of switch assembly 180 includes a board body 185 defining afirst end portion 186 a, a second end portion 186 b, and a centralportion 186 c. Central portion 186 c of board body 185 is configured toreceive activation button 182 thereon. More specifically, centralportion 186 c defines apertures 187 a (or other suitable engagementfeatures) to enable snap-fitting (or other suitable mechanicalengagement) of activation button 182 thereon. Central portion 186 cfurther defines circuit traces 187 b such that, upon mechanicalengagement of activation button 182 thereon, activation button 182 isalso electrically coupled to PCB 184. This configuration facilitatesassembly and reduces the possibility of improper connections. Circuittraces 187 b extend from central portion 186 c towards first end portion186 a of board body 185 on both the upper and lower faces of board body185 to enable connection of a pair of lead wires 310 (only one of whichis shown) of electrosurgical cable 300 thereto, e.g., via soldering.Circuit traces 187 b also extend from central portion 186 c towardssecond end portion 186 b of board body 185 on both the upper and lowerfaces of board body 185. A quick-connect receptacle 188 is disposed oneach of the upper and lower faces of body board 185 towards second endportion 186 b thereof in electrical communication with circuit traces187 b. Quick-connect receptacles 188 facilitate engagement of lead wirereceptacles 189 (only one of which is shown) therewith, thusfacilitating coupling of the lead wires 310 of jaw members 210, 220 withswitch assembly 180. More specifically, lead wire receptacles 189 areconfigured to slide into snap fit or other suitable engagement withquick-connect receptacles 188 to both mechanically engage lead wirereceptacles 189 with PCB 184 and electrically couple the lead wires 310of jaw members 210, 220 to corresponding portions of circuit traces 187b. As a result of the above-detailed configuration of switch assembly180, activation of activation button 182 initiates the supply of energyfrom the energy source (not shown) to jaw members 210, 220 such thatsuch energy may be conducted through tissue grasped betweentissue-contacting plates 214, 224 of jaw members 210, 220 to treattissue (see FIGS. 3A-4B).

Referring to FIGS. 17A-17H, the assembly of forceps 100 is detailed. Indetailing the assembly of forceps 100 hereinbelow, additional structuralfeatures and functional benefits of forceps 100 may be described and/orbecome apparent. Accordingly, despite being described in connection withthe assembly of forceps 100, the features of forceps 100 detailed herein(above or below) are not limited to assembly in the manner detailedbelow. Likewise, the advantageous order and manner of assembly of thecomponents of forceps 100 as detailed below is not limited to use withthe particular features of the various components of forceps 100detailed above or otherwise herein.

With initial reference to FIGS. 17A and 17B, inner frames 114, 124 ofshaft members 110, 120 are pre-assembled with the respective jaw members210, 220 thereon, as detailed above. Switch assembly 180 is alsopre-assembled together with electrosurgical cable 300, as also detailedabove. With inner frames 114, 124 pre-assembled with jaw members 210,220, respectively, knife 140 may then be operably coupled to inner frame114 of shaft member 110 such that knife 140 extends through longitudinalchannel 115 h of inner frame 114 and aperture 144 of knife 140 isaligned with longitudinal slot 115 e of inner frame 114. Thereafter,shaft members 110, 120 are aligned to enable pivot member 130 to beinserted through aperture 125 e of distal clevis portion 125 c of innerframe 124, pivot aperture 115 f of body plate 115 a of inner frame 114,and into keyed aperture(s) 125 f defined through the other side wall ofdistal clevis portion 125 c. Upon such positioning, slot 136 of pivotmember 130 receives a portion of knife 140. Body portion 132 of pivotmember 130 may be welded, e.g., via laser welding, to the portion of theside wall of distal clevis portion 125 c that surrounds keyedaperture(s) 125 f at this point or later on during the assembly process.Location recess 134′ of cap 134 of pivot member 130 (see FIG. 5C) isutilized during welding of pivot member 130 to distal clevis portion 125c, obviating the need to utilize a vision system to enable precisewelding. Location recess 134′ further serves as a “zero” position duringcomponent assembly, welding (as mentioned above in addition to otherwelding) and other fixation, and testing, e.g., jaw force testing, jawgap testing, and electrical testing.

Turning to FIG. 17C, with inner frames 114, 124 of shaft members 110,120 operably coupled to one another via pivot member 130 and with knife140 operably coupled to inner frame 114, a portion of outer housing 126of shaft member 120 is positioned on inner frame 124 and the lead wires310 of jaw members 210, 220 are routed therethrough. Once routed throughthe portion of outer housing 126 installed on inner frame 124, the leadwires 310 of jaw members 210, 220 are operably coupled to switchassembly 180 via connection of lead wire receptacles 189 withquick-connect receptacles 188 of switch assembly 180, therebyelectrically coupling jaw members 210, 220 with switch assembly 180 andelectrosurgical cable 300. Additionally, at this point, knife lockout170 is installed on inner frame 114 of shaft member 110.

With reference to FIG. 17D, handles 118, 128 are engaged within firsthalf-housing portions of outer housings 116, 126 of shaft members 110,120, respectively, although handles 118, 128 may alternatively bepre-assembled with the first half-housing portions of outer housing 116,126. First linkage 154 of knife deployment mechanism 150 is thenoperably positioned such that one of the pivot bosses 161 thereofextends through a corresponding aperture defined through the firsthalf-housing portion of outer housing 116. Thereafter, biasing member158 is operably coupled between first linkage 154 and handle 118, asdetailed above. The trigger 152 corresponding to the first half-housingportion of outer housing 116 is also engaged about the portion of thepivot boss 161 that extends outwardly from the first half-housingportion of outer housing 116.

Referring to FIG. 17E, the subassembly of FIG. 17C and the subassemblyof FIG. 17D are combined. More specifically, inner frames 114, 124 areoperable engaged within the respective first half-housing portions ofouter housing 116, 126. Further, switch assembly 180 and the distal endof electrosurgical cable 300 are seated within the first half-housingportion of outer housing 126 of shaft member 120.

Turning to FIG. 17F, once the subassemblies of FIGS. 17C and 17D arecombined as noted above, second linkage 156 of knife deployment assembly150 is engaged to first linkage 154 and knife 140 (through inner frame114 of shaft member 110). With the internal components of forceps 100 inplace, the second half-housing portions of outer housing 116, 126 aremoved into place to fully form outer housings 116, 126 and enclose theinternal components therein, as illustrated in FIG. 17G. Finally, asshown in FIG. 17H, the other trigger 152 of knife deployment mechanism150 is engaged with the corresponding pivot boss 161 of first linkage154 on the second half-housing side of outer housing 116 of shaft member110.

Once assembly is completed, e.g., as detailed above, testing may beperformed to ensure proper operation of forceps 100. Such testing mayinclude jaw force testing; testing using a gauge pin (not shown) to testthe maximum jaw aperture between jaw members 210, 220 at the distal tipsthereof; cut testing of the knife 140 using cut test media (not shown);testing of the gap distance between the tissue-contacting plates 214,224 of jaw members 210, 220 (as set by the one or more stop members 215b and/or beak sections 218 c of jaw members 210, 220) in theapproximated position thereof at various positions along the lengths ofjaw members 210, 220; and/or performing electrical continuity testing.

Referring to FIG. 17H, forceps 100, once fully assembled, defines afirst length “L1” extending distally from the midpoint of pivot member130 to the distal end of distal tip of jaw members 210, 220 (FIG. 1 ) ofend effector assembly 200 and a second length “L2” extending proximallyfrom the midpoint of pivot member 130 to the midpoint of handles 118,128. A ratio L2:L1 of the second length to the first length is fromabout 2.0 to about 4.0 to provide the surgeon witan expected feel. Morespecifically, a ratio L2:L1 ranging from about 2.0 to about 4.0 has beenfound to correspond to an expected feel such that when a surgeon pivotshandles 118, 128 towards or away from one another, jaw members 210, 220(FIG. 1 ) are pivoted relative to one another an expected amount orclose thereto. Ratios outside this range may require that the surgeonlearn the device to achieve desired movement of the jaw members 210, 220(FIG. 1 ), whereas forceps 100 provides an expected feel without theneed for, or minimal, learning. As an example without limitation, length“L1” may be about 4 cm and length “L2” may be about 14 cm, therebyproviding a ratio L2:L1 of 3.5.

Turning now to FIGS. 28-30 , forceps 100 is configured to facilitatetissue treatment, tissue division, and blunt tissue dissection. Inparticular, the various geometries, properties, and ratios of thefeatures of forceps 100, as detailed below, are provided such thatforceps 100 facilitates tissue treatment, tissue division, and blunttissue dissection. More specifically, these features provide forceps 100with long, fine, curved jaw members that allow for precision whenworking in and around critical tissue structures and other tight spaces,maximize line of sight, enable fine blunt tissue dissection, enabletissue division closer to the distal tip of forceps 100, and reducecooling times after energy application, all while providing reliabletissue seals. To the extent consistent, the aspects and features of thejaw members of forceps 100 detailed herein may likewise be utilized inconjunction with a shaft-based (endoscopic or open) surgical forceps, arobotic surgical forceps, or other suitable style instrument.

Referring in particular to FIG. 28 , it has been found that the abovemay be achieved by providing each jaw member with appropriate tipgeometry ratio(s). As the distal tip portions of both jaw members aredesigned the same, FIG. 28 only illustrates, and reference is only madeherein to, distal tip portion 280 of jaw member 220, keeping in mindthat the geometry ratio(s) of tip portion of jaw member 210 (FIG. 1 )are the same (taking into account tolerances).

As illustrated in FIG. 28 , jaw member 220 includes a distal tip portion280. Distal tip portion 280 of jaw member 220, in embodiments, is thearea defined within the concave side of a curved distal perimeter of jawmember 220 (as viewed from the top or bottom of jaw member 220). Morespecifically, distal tip portion 280 may be defined as the portion ofjaw member 220 encompassed by the half-ellipse “E” at the distal end ofjaw member 220 (as viewed from the top or bottom of jaw member 220). Insuch embodiments, distal tip portion 280 has a curved distal perimeter282 that defines the outer periphery of distal tip portion 280 (and thehalf circumference defined by the half-ellipse “E”), a full diameter 284which serves as a dividing line between distal tip portion 280 of jawmember 220 and the rest of jaw member 220, and a half-diameter or radius286 (owing to the fact that tip portion 280 is a half-ellipse ratherthan a full ellipse). Full diameter 284 is the minor diameter of thehalf-ellipse “E” and also defines the width dimension of distal tipportion 280 of jaw member 220, as distal tip portion 280 tapers distallyof full diameter 284 to a blunt distal end defined by curved distalperimeter 282. Radius 286 is the major radius of the half-ellipse “E.”

A width to length ratio of distal tip portion 280 is, in embodiments,from about 1.45 to about 1.70, in other embodiments, from about 1.50 toabout 1.65 and, in still other embodiments, from about 1.55 to about1.60. In other embodiments, the ratio is about 1.57. The width dimension“W1” of distal tip portion 280 is the largest width of distal tipportion 280 defined transversely across jaw member 220 and, thus, isdefined by full diameter 284. The length dimension “L3” of distal tipportion 280 is defined longitudinally along jaw member 220 and, thus, isdefined by radius 286, which extends from full diameter 284 to thedistal end of jaw member 220. Thus, in embodiments, the above ratioranges may likewise apply to the ratio of the full diameter of thehalf-ellipse “E” of distal tip portion 280 to the radius of thehalf-ellipse “E” of distal tip portion 280. The use of “about” withrespect to the above-noted ratios and otherwise herein accounts forgenerally accepted manufacturing, use, environmental, and measurementtolerances.

Referring also to FIG. 30 , a height to length ratio of jaw members 210,220 at the distal tip portions 280 thereof may be utilized together withor separately from the above-noted width to length ratios. The height tolength ratio may be, in embodiments, from about 2.25 to about 2.55, inother embodiments, from about 2.30 to about 2.50 and, in still otherembodiments, from about 2.35 to about 2.45. In other embodiments, theratio is about 2.40. The length dimension “L3” is the length of thedistal tip portion 280 of jaw member 220 (or likewise of jaw member 210,which is the same absent tolerances), as detailed above. The heightdimension “H1” is the height defined collectively by jaw members 210,220 at the distal tip portions 280 (more specifically, at full diameter284 of distal tip portion 280) thereof when jaw members 210, 220 aredisposed in the fully closed position, e.g., wherein a gap distancedefined between the distal tip portions 280 of jaw members 210, 220 isequal to or less than about 0.003 inches. In other embodiments, the gapdistance is equal to or less than about 0.025 inches; in yet otherembodiments, the gap distance is equal to or less than about 0.020inches; in still other embodiments, the gap distance is equal to or lessthan about 0.015 inches; and in still yet other embodiments, the gapdistance is equal to or less than about 0.010 inches. In embodiments,the distal tip portions 280 of jaw members 210, 220 may contact oneanother in the fully closed position, eliminating a minimum gap distancetherebetween.

Turning to FIGS. 28-29 , it has been found that facilitating tissuetreatment, tissue division, and blunt tissue dissection may additionallyor alternatively be achieved by providing each jaw member withappropriate curvature and/or taper geometry ratio(s). As the tipportions of both jaw members are designed the same, FIG. 29 onlyillustrates, and reference is only made herein to, tip portion 280 ofjaw member 220, keeping in mind that the geometry ratio(s) of tipportion of jaw member 210 (FIG. 1 ) are the same.

Jaw member 220 defines a curvature along at least a portion of thelength thereof and, more specifically, may include a proximal straightsection 292 defining a longitudinal axis 294 and a distal curved section296 that curves off of longitudinal axis 294. The proximal straightsection 292 may define a length of about 0.0 inches to about 0.125inches. Proximal straight section 292, in embodiments where provided, iscentered about longitudinal axis 294 (at least as viewed from a top orbottom view of jaw member 220) and defines a substantially constantwidth “W2” (wherein the use of “substantially” herein accounts forgenerally accepted manufacturing, use, environmental, and measurementtolerances). This width “W2” is measured transversely across jaw member220. A ratio of the width “W2” of proximal straight section 292 to thewidth “W1” of distal tip portion 280 (detailed above), in embodiments,is from about 1.60 to about 2.00, in other embodiments, from about 1.70to about 1.90 and, in still other embodiments, from about 1.75 to about1.85. In other embodiments, the ratio is about 1.80. In embodimentswhere no proximal straight section 292 is provided (i.e., where theproximal straight section 292 defines a length of 0.0 inches), thelongitudinal axis 294 is defined longitudinally through the mid-pointtransversely across the proximal end of jaw member 220, e.g., across theproximal edge of the tissue-contacting plate 224 of jaw member 220. Insuch embodiments, the width “W2” is defined transversely across theproximal end of jaw member 220, e.g., across the proximal edge of thetissue-contacting plate 224 of jaw member 220, with the above-notedratios applying similarly.

Distal curved section 296 of jaw member 220 defines a length “L4,” asmeasured along the longitudinal axis 294 from the position where jawmember 220 begins to curve to the position where a radius 286 of distaltip portion 280 (which symmetrically bisects distal tip portion 280)intersects curved distal perimeter 282 of distal tip portion 280. Distalcurved section 296 further defines a distance of curvature “D1,” asmeasured transversely from the longitudinal axis 294 to the positionwhere radius 286 of distal tip portion 280 meets curved distal perimeter282 of distal tip portion 280. A ratio of the length “L4” of distalcurved section 296 of jaw member 220 to the distance of curvature “D1”of distal curved section 296 of jaw member 220, in embodiments, is fromabout 2.40 to about 2.80, in other embodiments, from about 2.50 to about2.70 and, in still other embodiments, from about 2.55 to about 2.65. Inother embodiments, the ratio is about 2.60.

Turning momentarily to FIG. 31 , tissue-contacting plate 224 of jawmember 220 is shown, although the following may additionally oralternatively apply to tissue-contacting plate 214 of jaw member 210(FIGS. 3A-3B). As noted above, tissue-contacting plate 224 of jaw member220 defines a longitudinally-extending knife channel 225. The distalcurved section 296 of jaw member 220 defines an angle of curvature “θ,”in embodiments, from about 15 degrees to about 25 degrees; in otherembodiments from about 17 degrees to about 23 degrees, in otherembodiments from about 19 degrees to about 21 degrees; and in yet otherembodiments, from about 19.5 degrees to about 20.5 degrees. Inembodiments where jaw member 220 does not include a proximal straightportion 292 (FIG. 29 ) and, thus, distal curved section 296 of jawmember 220 constitutes the entirety of tissue-contacting plate 224,angle of curvature “θ” is defined between the longitudinal axis 294,which passes through a proximal transverse center point “A” of knifechannel 225 at the proximal end of knife channel 225, and a line segmentconnecting proximal transverse center point “A” with a distal transversecenter point “B.” Distal transverse center point “B” is transverselycentered across the distal end of knife channel 225 and is disposed onthe arcuate interior edge of tissue-contacting plate 224 that definesthe closed distal end of knife channel 225. Alternatively, distaltransverse center point “B” may be defined as the point at distal tipportion 280 of jaw member 220 where the half circumference defined bythe half-ellipse “E” is intersected by the full diameter 284 (see FIGS.28 and 29 ).

In embodiments where jaw member 220 includes a proximal straight portion292, and, thus, distal curved section 296 of jaw member 220 constitutesonly a portion of tissue-contacting plate 224, proximal transversecenter point “A” of knife channel 225 is defined at the transverse line“T” dividing the proximal straight section 292 from the distal curvedsection 296 (see FIG. 29 ), with the above-detailed angles applyingsimilarly.

With additional reference to FIG. 30 , with respect to height taper ofjaw members 210, 220, the ratio of proximal height to distal height is,in embodiments, from about 1.80 to about 2.10, in other embodiments,from about 1.85 to about 2.05 and, in still other embodiments, fromabout 1.90 to about 2.00. In other embodiments, the ratio is about 1.94.The proximal height “H2” is the height defined collectively by jawmembers 210, 220 at the position where jaw member 210 emerges fromdistal clevis portion 125 c, as viewed from a side view of jaw members210, 220, when jaw members 210, 220 are disposed in the fully closedposition. The distal height “H1” is the height defined collectively byjaw members 210, 220 at the distal tip portions 280 (more specifically,at full diameter 284 of distal tip portion 280) thereof when jaw members210, 220 are disposed in the fully closed position.

Referring still to FIG. 30 , it has further been found that facilitatingtissue treatment, tissue division, and blunt tissue dissection may beachieved by additionally or alternatively providing a ratio of thedistance between the pivot and the proximal and distal ends of thelockbox configuration of shaft members 110, 120. More specifically, aratio of the distance from the center of the pivot to the proximal endof the lockbox configuration “D3” to the distance from the center of thepivot to the distal end of the lockbox configuration “D2” is, inembodiments, from 0.90 to about 1.10, in other embodiments, from about0.95 to about 1.05 and, in still other embodiments, from about 0.97 toabout 1.01. In other embodiments, the ratio is from about 0.98 to about0.99. The center of the pivot is defined as the center of pivot 130. Theproximal end of the lockbox configuration is defined at the proximal endof the body of distal clevis portion 125 c, not including the proximaltail portion thereof. More specifically, the proximal end of the lockboxconfiguration is the position at which the proximally-facing edge ofdistal clevis portion 125 c changes slope, thus indicating thetransition from the body of distal clevis portion 125 c to the proximaltail portion thereof. In other embodiments, the proximal end of thelockbox configuration is the distal end of inner frame 124 of shaftmember 120, which extends within the proximal tail portion of distalclevis portion 125 c but does not extending into the body portionthereof. The distal end of the lockbox configuration is defined at theposition where jaw member 210 emerges from distal clevis portion 125 c,as viewed from a side view when jaw members 210, 220 are disposed in thefully closed position.

A ratio of the length “L1” extending from the midpoint of pivot member130 to the distal end of distal tip of jaw members 210, 220 (see FIGS. 1and 17H) to the distance from the midpoint of pivot member 130 to thedistal end of the lockbox configuration, “D2,” has also been found tofacilitating tissue treatment, tissue division, and blunt tissuedissection. This ratio, L1/D2, in embodiments, is from about 1.80 toabout 2.40; in other embodiments, from about 1.90 to about 2.30; instill other embodiments, from about 2.00 to about 2.20; and, in yetother embodiments, about 2.09.

Referring generally to FIGS. 28-30 , it has further been found that,additionally or alternatively, that jaw stiffness is important. Jawstiffness provides structural support but also defines the flexibilityof the jaws, which flexion forms part of the overall spring system offorceps 10 (FIG. 1 ) to provide a suitable jaw force for treating, e.g.,sealing, tissue grasped between jaw members 210, 220. The stiffness ofjaw members 210, 220 is thus the ability of jaw members 210, 220 toresist deflection away from one another, e.g., in response to force(s)applied substantially normal to the tissue-contacting surfaces thereof.

Stiffness, more specifically, is measured as displacement of distal tipportion 280 in response to a force applied at distal tip portion 280 ina direction substantially normal to the tissue-contacting surface of thejaw member 210, 220. The displacement may be measured relative to thecenter of pivot 130 or, in other embodiments, may be measured relativeto the position where jaw member 210 emerges from distal clevis portion125 c, as viewed from a side view of jaw members 210, 220.

Overall, the stiffness of either or both jaw members 210, 220, fromeither measurement point, may be from about 80 lb/in to about 300 lb/in;in embodiments, from about 90 lb/in to about 250 lb/in; and, inembodiments, from about 100 lb/in to about 200 lb/in. The jaw members210, 220 may have similar or different stiffnesses. The stiffness of jawmember 210 as measured relative to the center of pivot 130 may be, inembodiments, from about 80 lb/in to about 160 lb/in; in otherembodiments, from about 100 lb/in to about 140 lb/in; and in still otherembodiments, from about 110 lb/in to about 130 lb/in. The stiffness ofjaw member 210, as measured relative to the position where jaw member210 emerges from distal clevis portion 125 c may be, in embodiments,from about 100 lb/in to about 180 lb/in; in other embodiments, fromabout 120 lb/in to about 160 lb/in; and, in yet other embodiments, fromabout 130 lb/in to about 150 lb/in.

The stiffness of jaw member 220 as measured relative to the center ofpivot 130 may be, in embodiments, from about 110 lb/in to about 190lb/in; in other embodiments, from about 130 lb/in to about 170 lb/in;and in still other embodiments, from about 140 lb/in to about 160 lb/in.The stiffness of jaw member 220, as measured relative to the positionwhere jaw member 210 emerges from distal clevis portion 125 c may be, inembodiments, from about 145 lb/in to about 225 lb/in; in otherembodiments, from about 165 lb/in to about 205 lb/in; and, in yet otherembodiments, from about 175 lb/in to about 195 lb/in.

The various embodiments disclosed herein may also be configured to workwith robotic surgical systems and what is commonly referred to as“Telesurgery.” Such systems employ various robotic elements to assistthe surgeon and allow remote operation (or partial remote operation) ofsurgical instrumentation. Various robotic arms, gears, cams, pulleys,electric and mechanical motors, etc. may be employed for this purposeand may be designed with a robotic surgical system to assist the surgeonduring the course of an operation or treatment. Such robotic systems mayinclude remotely steerable systems, automatically flexible surgicalsystems, remotely flexible surgical systems, remotely articulatingsurgical systems, wireless surgical systems, modular or selectivelyconfigurable remotely operated surgical systems, etc.

The robotic surgical systems may be employed with one or more consolesthat are next to the operating theater or located in a remote location.In this instance, one team of surgeons or nurses may prep the patientfor surgery and configure the robotic surgical system with one or moreof the instruments disclosed herein while another surgeon (or group ofsurgeons) remotely control the instruments via the robotic surgicalsystem. As can be appreciated, a highly skilled surgeon may performmultiple operations in multiple locations without leaving his/her remoteconsole which can be both economically advantageous and a benefit to thepatient or a series of patients.

The robotic arms of the surgical system are typically coupled to a pairof master handles by a controller. The handles can be moved by thesurgeon to produce a corresponding movement of the working ends of anytype of surgical instrument (e.g., end effectors, graspers, knifes,scissors, etc.) which may complement the use of one or more of theembodiments described herein. The movement of the master handles may bescaled so that the working ends have a corresponding movement that isdifferent, smaller or larger, than the movement performed by theoperating hands of the surgeon. The scale factor or gearing ratio may beadjustable so that the operator can control the resolution of theworking ends of the surgical instrument(s).

The master handles may include various sensors to provide feedback tothe surgeon relating to various tissue parameters or conditions, e.g.,tissue resistance due to manipulation, cutting or otherwise treating,pressure by the instrument onto the tissue, tissue temperature, tissueimpedance, etc. As can be appreciated, such sensors provide the surgeonwith enhanced tactile feedback simulating actual operating conditions.The master handles may also include a variety of different actuators fordelicate tissue manipulation or treatment further enhancing thesurgeon's ability to mimic actual operating conditions.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. While several embodiments of the disclosure have been shownin the drawings, it is not intended that the disclosure be limitedthereto, as it is intended that the disclosure be as broad in scope asthe art will allow and that the specification be read likewise.Therefore, the above description should not be construed as limiting,but merely as exemplifications of particular embodiments. Those skilledin the art will envision other modifications within the scope and spiritof the claims appended hereto.

What is claimed is:
 1. An electrosurgical forceps, comprising: first andsecond shaft members; first and second jaw members extending distallyfrom the respective first and second shaft members, each of the firstand second jaw members including a distal tip portion defined as an areawithin a concave side of a curved distal perimeter of the distal tipportion; and a pivot coupling the first and second shaft members withone another such that the first and second shaft members are movablerelative to one another between a spaced-apart position and anapproximated position to move the first and second jaw members relativeto one another between an open position and a closed position, wherein aratio of a width of the distal tip portion of each of the first andsecond jaw members to a length of the distal tip portion of each of thefirst and second jaw members is in a range from about 1.45 to about1.70.
 2. The electrosurgical forceps according to claim 1, wherein theratio is in a range of from about 1.50 to about 1.65.
 3. Theelectrosurgical forceps according to claim 1, wherein the ratio is in arange of from about 1.55 to about 1.60.
 4. The electrosurgical forcepsaccording to claim 1, wherein the ratio is about 1.57.
 5. Theelectrosurgical forceps according to claim 1, wherein the distal tipportion of each of the first and second jaw members defines ahalf-ellipse, and wherein the curved distal perimeter defines ahalf-circumference of the half-ellipse.
 6. The electrosurgical forcepsaccording to claim 5, wherein the width is a minor diameter of thehalf-ellipse.
 7. The electrosurgical forceps according to claim 5,wherein the length is a major radius of the half-ellipse.
 8. Theelectrosurgical forceps according to claim 1, wherein each of the firstand second jaw members is curved along a portion of a length thereof. 9.The electrosurgical forceps according to claim 1, wherein a lockboxconfiguration surrounds the pivot.
 10. An electrosurgical forceps,comprising: first and second shaft members; first and second jaw membersextending distally from the respective first and second shaft members,each of the first and second jaw members defining a longitudinal axisand a curved distal section curving off of the longitudinal axis, thecurved distal section of each of the first and second jaw membersdefining a length and including a distal tip portion defined as an areawithin a concave side of a curved distal perimeter of the distal tipportion; and a pivot coupling the first and second shaft members withone another such that the first and second shaft members are movablerelative to one another between a spaced-apart position and anapproximated position to move the first and second jaw members relativeto one another between an open position and a closed position, wherein aratio of the length of the curved distal section of each of the firstand second jaw members to a distance the distal tip portion of each ofthe first and second jaw members is displaced from the respectivelongitudinal axis of that jaw member is in a range from about 2.40 toabout 2.80.
 11. The electrosurgical forceps according to claim 10,wherein the ratio is in a range of from about 2.50 to about 2.70. 12.The electrosurgical forceps according to claim 10, wherein the ratio isin a range of from about 2.55 to about 2.65.
 13. The electrosurgicalforceps according to claim 10, wherein the ratio is about 2.60.
 14. Theelectrosurgical forceps according to claim 10, wherein the distal tipportion of each of the first and second jaw members defines ahalf-ellipse, wherein the curved distal perimeter of each of the firstand second jaw members defines a half-circumference of the half-ellipse,and wherein the length and the distance are measured to a point where asymmetrically bisecting radius of the half-ellipse meets the curveddistal perimeter.
 15. The electrosurgical forceps according to claim 10,wherein each of the first and second jaw members further includes astraight proximal section centered on the longitudinal axis thereof, thecurved distal section extending from the straight proximal section. 16.The electrosurgical forceps according to claim 15, wherein the straightproximal section defines a length of up to about 0.125 inches.
 17. Theelectrosurgical forceps according to claim 10, wherein the curved distalsection of each of the first and second jaw members defines an angle ofcurvature of about 15 degrees to about 25 degrees.
 18. Theelectrosurgical forceps according to claim 10, wherein the curved distalsection of each of the first and second jaw members defines an angle ofcurvature of about 17 degrees to about 23 degrees.
 19. Theelectrosurgical forceps according to claim 10, wherein the curved distalsection of each of the first and second jaw members defines an angle ofcurvature of about 19 degrees to about 21 degrees.